Henry Ford Hospital Medical Journal


Effects have been studied of induction of aminonucleoside-nephrosis in the rat on kidney cortex lysosomal acid proteinase activity (pH 3.2) and on such activity in the cytosol from which the lysosomes were isolated. In parallel with the onset of the massive proteinuria of the disease process but not preceding this effect, activity in the cytosol fraction was significantly increased. Significantly increased activity in the lysosomal fraction, on the other hand, was not observed until the proteinuria was well-established. Comparative study of the release of acid proteinase activity, from intact lysosomes isolated from normal and from aminonucleoslde-nephrotic rat kidneys, suggest-in the latter case-either increased permeability or increased lysis of lysosomal membranes, permitting release of the proteolytic activity. Absence of any in vivo or direct effect of aminonucleoside on the release of the acid proteinase from normal intact kidney lysosomes, however, cautions against this interpretation of the findings.